Linux系统之jq工具的基本使用

yum install -y epel-release

[root@jeven ~]# yum search jq
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * epel: mirrors.tuna.tsinghua.edu.cn
====================================================== N/S matched: jq ======================================================
drupal7-jquery_update.noarch : Upgrades the version of jQuery in Drupal core to a newer version of jQuery
jq-devel.x86_64 : Development files for jq
js-jquery-mousewheel.noarch : A jQuery plugin that adds cross-browser mouse wheel support
js-jquery-ui.noarch : jQuery user interface
js-jquery-ui-touch-punch.noarch : Touch Event Support for jQuery UI
python-XStatic-JQuery-Migrate.noarch : JQuery-Migrate (XStatic packaging standard)
python-XStatic-JQuery-TableSorter.noarch : JQuery-TableSorter (XStatic packaging standard)
python-XStatic-JQuery-quicksearch.noarch : JQuery-quicksearch (XStatic packaging standard)
python-XStatic-jQuery.noarch : jQuery 1.10.2 (XStatic packaging standard)
python-XStatic-jquery-ui.noarch : jquery-ui (XStatic packaging standard)
python-tw2-jqplugins-flot.noarch : jQuery flot (plotting) for ToscaWidgets2
python-tw2-jqplugins-gritter.noarch : jQuery gritter (growl-like pop-ups) for ToscaWidgets2
python-tw2-jqplugins-jqplot.noarch : Toscawidgets2 wrapper for the jqPlot jQuery plugin
python-tw2-jqplugins-ui.noarch : jQuery UI for ToscaWidgets2
python-tw2-jquery.noarch : jQuery for ToscaWidgets2
jq.x86_64 : Command-line JSON processor
js-jquery.noarch : JavaScript DOM manipulation, event handling, and AJAX library
js-jquery1.noarch : JavaScript DOM manipulation, event handling, and AJAX library
nodejs-extend.noarch : Port of jQuery.extend for node.js and the browser
python-pyquery.noarch : A jQuery-like library for python
python2-XStatic-DataTables.noarch : DataTables jquery javascript framework (XStatic packaging standard)
xstatic-datatables-common.noarch : DataTables jquery javascript framework (XStatic packaging standard)

  Name and summary matches only, use "search all" for everything.

yum -y install jq.x86_64

[root@docker yum.repos.d]# jq -V
jq-1.6

wget https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64  -O   /usr/local/bin/jq

chmod +x /usr/local/bin/jq

[root@jeven ~]# jq --help
jq - commandline JSON processor [version 1.6]

Usage:	jq [options] <jq filter> [file...]
	jq [options] --args <jq filter> [strings...]
	jq [options] --jsonargs <jq filter> [JSON_TEXTS...]

jq is a tool for processing JSON inputs, applying the given filter to
its JSON text inputs and producing the filter's results as JSON on
standard output.

The simplest filter is ., which copies jq's input to its output
unmodified (except for formatting, but note that IEEE754 is used
for number representation internally, with all that that implies).

For more advanced filters see the jq(1) manpage ("man jq")
and/or https://stedolan.github.io/jq

Example:

	$ echo '{"foo": 0}' | jq .
	{
		"foo": 0
	}

Some of the options include:
  -c               compact instead of pretty-printed output;
  -n               use `null` as the single input value;
  -e               set the exit status code based on the output;
  -s               read (slurp) all inputs into an array; apply filter to it;
  -r               output raw strings, not JSON texts;
  -R               read raw strings, not JSON texts;
  -C               colorize JSON;
  -M               monochrome (don't colorize JSON);
  -S               sort keys of objects on output;
  --tab            use tabs for indentation;
  --arg a v        set variable $a to value <v>;
  --argjson a v    set variable $a to JSON value <v>;
  --slurpfile a f  set variable $a to an array of JSON texts read from <f>;
  --rawfile a f    set variable $a to a string consisting of the contents of <f>;
  --args           remaining arguments are string arguments, not files;
  --jsonargs       remaining arguments are JSON arguments, not files;
  --               terminates argument processing;

Named arguments are also available as $ARGS.named[], while
positional arguments are available as $ARGS.positional[].

See the manpage for more options.

-c               紧凑而不是漂亮的输出;
-n               使用`null`作为单个输入值;
-e               根据输出设置退出状态代码;
-s               将所有输入读取（吸取）到数组中；应用过滤器;
-r               输出原始字符串，而不是JSON文本;
-R               读取原始字符串，而不是JSON文本;
-C               为JSON着色;
-M               单色（不要为JSON着色）;
-S               在输出上排序对象的键;
--tab            使用制表符进行缩进;
--arg a v        将变量$a设置为value<v>;
--argjson a v    将变量$a设置为JSON value<v>;
--slurpfile a f  将变量$a设置为从<f>读取的JSON文本数组;
--rawfile a f    将变量$a设置为包含<f>内容的字符串;
--args           其余参数是字符串参数，而不是文件;
--jsonargs       其余的参数是JSON参数，而不是文件;
--               终止参数处理;

[root@jeven ~]# cat name.json 
{
   "name": "John",
   "age": 30,
   "city": "New York",
   "hobbies": ["reading", "running", "traveling"],
   "education": {
      "degree": "Master's",
      "major": "Computer Science",
      "school": "University of California"
   }
}

[root@jeven ~]# jq keys name.json 
[
  "age",
  "city",
  "education",
  "hobbies",
  "name"
]

[root@jeven ~]# jq .hobbies  name.json 
[
  "reading",
  "running",
  "traveling"
]

[root@jeven ~]# jq .[] name.json 
"John"
"30"
"New York"
[
  "reading",
  "running",
  "traveling"
]
{
  "degree": "Master's",
  "major": "Computer Science",
  "school": "University of California"
}

[root@jeven ~]# cat name.json  |jq 
{
  "name": "John",
  "age": 30,
  "city": "New York",
  "hobbies": [
    "reading",
    "running",
    "traveling"
  ],
  "education": {
    "degree": "Master's",
    "major": "Computer Science",
    "school": "University of California"
  }
}

[root@jeven ~]# jq '.[] | length' name.json 
4
2
8
3
3

[root@jeven ~]# echo '{ "jven": { "aa": { "bb": 123 } } }' | jq '.'
{
  "jven": {
    "aa": {
      "bb": 123
    }
  }
}

[root@jeven ~]# jq .[] name.json  | grep school
  "school": "University of California"